Steroid injections given to mothers at the peril of giving birth prematurely are probable to deliver babies with lower body weights, says a new study.

According to the study, pre-term babies whose mothers received Antenatal Corticosteroid Therapy (ACT) on average weighed 220 grams less than infants who had not received treatment.

The difference in weight was around 141 grams for near term babies and 89 grams for full-term babies. In addition, babies who received ACT yet delivered at term were also smaller in size when matched against infants given birth at term without the treatment.

"We have known from animal studies that steroid treatment could affect fetal growth. It is still unclear whether the reduction in birth weight of the treated infants is directly caused by the drug or due to the complications that led to the treatment," said Professor Alina Rodriguez from the University of Lincoln.

"This study adds weight to calls for a review of the current guidelines for management of threatened pre-term birth and for who should receive steroid treatment," Rodriguez added.

For the study, published in the journal PLOS Medicine, the team used data from 2,78,508 births to perceive if the link between reduced birth weight and size was related to the steroid treatment or to some other factors.

The study as well showed that more than four percent of children were born pre-term (before 37 weeks).

A total of 4,887 women received ACT, and 2,173 exposed babies were born at term (37 weeks). The fact that this treatment may cut down the fetal growth should be considered in future research and recommendations, suggested Marjo-Riitta Jarvelin, Professor from the varsity.

Across the world, about 1.5 million babies are born prematurely every year. Complications consequent from premature birth, particularly those related to breathing difficulties, are the leading source of death in infants and morbidity in survivors. Thus, ACT is used before birth to help mature the lungs quickly.